Neurolinguistics for Direct-Speech BCIs: From Accuracy to Phonology-Structured Error Anatomy

Neurolinguistics investigates how language is represented, processed, and disrupted in thehuman brain by combining evidence from language disorders, lesion-deficit mapping, functionalneuroimaging, and electrophysiology. In parallel with these foundational aims, neurolinguisticsincreasingly intersects with neurotechnology, particularly brain-computer interfaces (BCIs) thattarget communication restoration. Within this translational line, direct-speech BCIs (DS-BCIs)aim to decode speech production processes directly from neural activity. This makes DS-BCIwork, by construction, a neurolinguistic problem: it requires explicit assumptions about whatcounts as speech production content, which representational level is being targeted, and howexperimental designs avoid conflating production with perception.